Kristian Hogsberg, Red Hat Xorg developer and the key person behind successful projects such as AIGLX, has now started working on a new project called Wayland, a tiny display server and compositing manager.

well, i'm into SW engineering too, but nonetheless i believe one has to be a little more pragamatic than to unconditionally accept such conclusions as those written in that article...

maintaining an old codebase instead of rewriting it from scratch does indeed make sense - when you have a working product, when you need to maintain regular and tight release cycles, or be certain not to miss a deadline, it's better to add features, or cleanup or optimize in a cumulative fashion instead of starting anew

Since a program is a solution to a problem, then if the problem changes, it makes sense to find a new solution instead of trying to shoehorn old solutions "just because it exists"
in the case of a GUI architecture for a *desktop* Operating system, it makes sense to try and implement a clean design when the existing one does not actually work (as in accelerated *redirected* rendering on X) or is not workable (which is not the same, meaning that the effort taken by trying and update a codebase yields too little gains) and/or does not actually fulfills requirements any more

and the requrements of today's desktop systems - and users- are not the same as when X was conceived... today one wants to:
have a look and feel, as consistent as possible throughout the desktop;
have a desktop experience ( made of moving windows, watching media, etc )as smooth as possible;
exploit modern HW (given that even low end ones support TL and shaders) as fully as possible;

remoting the desktop, which requires network transparency (in turn, the solution to the problem of doing administration on a server without being physically in touch with it - or sharing a single machine's computing power across multiple users ) is no more a *stringent* requirement for the average dektop user (who btw needs as much computing power as the machine can give, all for himself )and has better and OS agnostic solutions (VNC in primis)
primitive rendering in the server is no more a requirement when applications, or the major portable toolkits, already have multiple render paths, for the local or remote cases, for rendering internally or using X11, or other libraries, and in some cases aim towards full HW acceleration (via common standard such as openvg)
nor is in-server text rendering, for the same reasons and because noone else uses the X font format other than X itself

look and feel customization can be retained in a more efficient and simple way by having graphic server / app server plugins implements what is now done in the window manager

all in all, there's no reason the FOSS world cannot look at what is done elsewhere (BeOS, NextStep, if not OSX or Haiku) and implement a streamlined app server with an optional X server for legacy support - no reason apart from NIH syndrome...